In Japanese Unexamined Patent Application No. 2006-096218, a conventional brake device for a vehicle is disclosed. A driver input amount is detected by a brake pedal stroke or master cylinder pressure, for example, and based on the detected driver input and a driver demand deceleration characteristic map, driver demand deceleration is calculated. To achieve this calculated demand deceleration, an add-on brake force will be generated to the vacuum booster output from a master cylinder (basic brake fluid pressure) and applied to a wheel by a feed-forward control.
In that device, the add-on brake force is defined as a part of deceleration amount to be added to the basic deceleration amount, which is attributable to a base brake fluid portion, so that the driver demand deceleration will be obtained. The add-on brake force may be obtained by either a regenerative braking and/or a pump up pressure portion. For example, the maximum value for the add-on brake portion may be set to correspond to a maximum regenerative amount, and an attempt will be made that the sum total of the base fluid pressure portion and a regenerative brake portion would meet the driver's brake demand as much as possible. In the event that the sum is not enough to meet the driver's demand, then the shortage of deceleration amount will be compensated for by a pump up of the master cylinder pressure attained by a conventional vehicle dynamics control (VDC) brake pressure unit, which is interposed between the master cylinder and wheel cylinders and generates a higher wheel cylinder pressure than the master cylinder pressure by way of a pump-up pressure increase.